Hydraulic pressure booster



p 1942- J. H. M CORMICK I 2,296,647

HYDRAULIC PRESSURE BOOSTER Filed Feb. 28, 1941 2 Sheets-Sheet 1INVENTOR.

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BY QQ ML ATTORNEYS.

Sept. 22, 1942. J, H, MCCQRWCK 2,296,647

HYDRAULI C PRES SURE BOOSTER Filed Feb. 28, 1941 2 Sheets-Sheet 2 INVENT OR.

ATTORNEYS.

Patented Sept. 22, 1942 U N l TED STAT E. S PAT E NT" QF-FICE HYDRAULICPRESSURE BOOSTER J ohn' H. McCormick, Racine, Wis., assignor to- Racine'Tool & Machine Company, Racine, Wis., a corporation of Wisconsin.

Application February 28, 1941, Serial No. 381,046

4 Claims.

The invention relates to hydraulic pressure boosters.

The general object of the invention is to provide a combined pump andmotor device of the differential piston type in which a pressure fluidat low pressure acting against the larger diameter of the piston is usedto raise the pressure of an operating fluid, preferably a portion of thelow pressure fluid, to the desired higher pressure. The pump and motordevice of the present invention is double acting, and the pressure ofthe higher pressure fluid is practically continuous through theoperation of an automatically operated reversing valve whose movementsare positively controlled by'auxiliary valves which are in turncontrolled both by each other, by the piston, and by the pressure of themotive fluid.

A further object of the invention is to provide a pump and motor of thetype above described in which the entire area of the high and lowpressure pistons may be used to drive the piston;

The invention further consists in the several features hereinafter setforth and more particularly defined by claims at the conclusion hereof;

In the drawings:

Fig. 1 is a vertical sectional view of a device embodying the inventionin one of its operating positions;

Fig. 2 is a vertical sectional view similanto Fig. 1 showing certainmodifications.

The combined motor and pump comprises a low pressure cylinder Sand highpressure cylinders 6, 6' alined therewith and with a double actingdifferential piston -'I having parts reciprocating in said cylinders Thecylinder is stormed in a casing 8 and the cylinders 6 in end plates 9and 9' secured in a fluid-tight manner to the casing 8.

A main piston type reversing valve I ll 'Works in he casing 8 having alow pressure supply conduit II, and passages I2, I2 respectivelyconnecting opposite ends of the cylinder 5with pas-' sages or holes I3in the cylindrical valve liner I4. The conduit I I connects with holesI5in said liner. The valve 8 has annular recesses I6 therein on oppositesides-of a central part I1 whereby the conduit II will connect witheitherthe passage I2 or the passage I2. Instead of being directlyoperated by the hydraulic fluid, the valve 8 has a lost motionconnection through a rod I8, loosely mounted in it and of greaterlength, with hydraulically operated rams t9,- I9 workingin bores 20, 20formed in the end plates 9 and 9' and alined with the bore in the linerI4.

Passage of hydraulic fluid to the bores 20 and 20 is through passagesZland 2| formed in the respective end plates and each controlled by itsown differential piston'type control valve 22 or The control valves 22and 22 work respectively in differentially alined bores 23, 24 and 23',24', the bores Y23 and 23'kbeing of smaller diameter and having annularenlargements25, 26, and 21 and 25, 26, and 21' therein, respectively.The enlargements 25 and 25 connectb'ycored passages 28" and 2B in'thcasing 8 with the inlet passage I I, the enlargements 26*:and 26'connect with the passages 2I'laml 2| and the enlargements 2'! and 21'connect'with passages 29 and 29' which are connected with the exhaust orreturn connection to the fluid supply tank. A port 30 from the passage2| connects through exterior piping 3| with a port 32 communicatingWiththe bore 24; and a port 30" connects through exterior piping 3| witha port'32' communicating with the bore- 24'. The liner I 4'has'exhaust'ports 33 and 33' which'connect withpermanentexhaust'chambers 34; 34' that in turn are connected by suitable pipingwith the supply tank.

For allowing any'leakage'from'the larger diameter parts of the valves 22and 22" to quickly escape to exhaust each of these valveshas alongitudinal passage 35 connected'by ports 36 and 31 wherebyleakage fromthe space adjacent bores 23 or 23' may escape through port 31, passage35j and port-3B 'to the exhaust including the enlargement Z'I'or 21' andpassage 29 or 29'.

In order to allow the low pressure fluid to act on the entire area ofeach end of the piston-I, the back end of each high pressure end isrelieved to provide a space38 'whichis' connected by a diametricallydisposed passage 39'with a centrally disposed passage 4|] leading to thehigh pressure bore of the cylinder 6 or 6 whose outer end is controlledby a flat seatedsp'ring closed-check valve 4| or M, eachmounted tocooperate with a removable seatmember '42 in the passage 40 secured inposition by a sleeve nut 43. Each check valve has a sleeve guideextension 44 provided with passages 4-5"adjacent the seating portion ofsaid valve.

The high pressure bore 6' has passages"46'=:and 41 connected. to a highpressure outlet passage 48, and the high'pressureboret' has-passages 46and 4'! connected to the high pressure outlet passage 48. A springseated discharge check valve 49 controls the discharge from'th'e passage41 to the passage 48, and a similar valve 49" controls the dischargefrom the passage 41' to the passage 48.

The drawing shows the device about to start on its pumping stroke towardthe right, the space 38 in front of the left hand face of the piston Ibeing filled with low pressure oil, some of which has passed by thecheck 4| to fill the cylinder space 6 in front of the high pressureportion of the piston This low pressure oil is being admitted to thedevice through the low pressure inlet II, holes I5, recess I6 in valveI0, ports I3, passage I2, space 38, and through passages 39 and 40 pastcheck valve 4| to cylinder space 6' and its conmeeting passages whichare under these conditions cut off from the high pressure outlet 48. At

the same time low pressure oil passes from the inlet I and passage 28'to enlargement 25' from which it proceeds through part of bore 23 andenlargement 26 to passage 2| and bore 24 acting on'th'e'part-of saidvalve 22 of larger diameter'and also connecting the smallerdiameterportion of this; valve 22 through enlargements 26 and 2| andpassage 20 with the exhaust or supply tank. At the same time the forwardend of bore-24 is connected to the exhaust'through piping 3 I passage 2I enlargements 26 and 21 and-passage;29; Under the conditions mentionedabovethe piston 'l'proceeds to move to the right forcing the fluid atthe low pressure side of cylinder 5 adjacent the cylinder-6 out theexhaust through the passages I2, I3, and 33 and forcing the fluid in thehigh pressure cylinder 6 into the passages 46 and 41 past the dischargevalve 49 and into thedi'scharge passage 48 until said piston strikes theinner end 50 of the valve 22 and shifts this valve to'the'right. Whenthis occurs, the valve 22 moves to the same position relative to thecylinder 6 as *is shown in connection with-the valve 22' and cylinder 6.Under these conditions theenlarg'ements and 26 are connected to thelow'pressure oil through the passage'28- and inlet I|,'so 'that'some ofthis oil may flow into the passage 2| to' the bore 20 in front oftheram'I9, and also'sorne of it will flow throughpipe'3l to the largerdiameter'bore 24" and act upon the larger diameter part of the piston ofthe valve 22 causing it to be shifted from its leftward position shownin the drawings toward the right so as to bring its smaller inner end50' into position to be struck by the piston as it nears the end of itsstroke toward the leftandalso connect the passage 2|" and enlargement26' with enlargement 2'! andpassage 29' to the exhaust or supply tank,thus'relieving the oil'pressure ahead of ram I9 andpermittingth'e lowpressure oil flowing into th'e'forward'part of bore 20 to act on ram I9and pin I8 so asto shift the reversing valve I0 toward the left. It'isalso to be noted that'the connection of the valve 22 with the exhaustalso connects the bore 24 through piping 3| with the exhaust or supplytank, so thatthere is no tendency for'the valve 22 to change theposition into which it has'been shifted by the piston. As soon asthere've'rsing'valve I0 reaches its leftward position; the low pressureoil "from passage II is admitted byvalve lflto'passage I2 while passageI2 is "connectedwiththe exhaust with the result that the piston I in"its right hand position has its right end acted upon by low przs'sureoil in the same way as that shown in the drawing on its left end, andits left end is relieved of pressure with the result that the piston ispushed from the right to the'left, and the oil in the bore 0 in front ofthe smaller diameter left end part of the piston I isforced throughpassages 46' and 41 past opened check valve 49 to the high pressurepassage 48, and when the piston I completes its movement to the left, itshifts the valve 22' to the left to the position shown in the drawing toconnect the bore 20' with the low pressure oil so as to shift the valveI0 to the position shown, and the cycle of operations is then repeated.

From the foregoing it will be noted that it is necessary to effect acomplete movement of one of the auxiliary valves 22 or 22 before theother is moved and that this latter valve is hydraulically moved andhydraulically held in a position to be struck and moved by the piston 1before the reversal of the reversing valve can take place, and thatwhile one auxiliary valve is hydraulically held in a tripping positionby low pressure oil, the other auxiliary valve is held in a non-trippingposition by suction or exhaust pressure on its larger diameter end. Itwill, therefore, be noted that the arrangement providesa hydraulicinterlocking action between the two auxiliary valves 22, 22' and thereversing valve I0.

In some instances it is desired to use different hydraulic fluids forthe low pressure motor' and the high pressure pump, and under thesecondi tions the low pressure oil is separate from the high pressurefluid, such as water, as shown in the apparatus of Fig. 2-in which thenumeral I05 designates the low pressure cylinder and I06 and I06 thehigh pressure cylinderswith the differential piston I01 working in thesecylinders, there being suitable packing glands 108 through which thehigh pressure end I09 and I09 of the piston I01 passes in order toprevent leakage between the high and low pressure cylinders. In thismodified form the high pressure ends func-' tion as ordinary plungertype pumps, the suction stroke of the piston I01 drawing water or otherpress operating fluid past suction inlet check valve 60' into the pumpchamber including the short pipe 6| and the delivery stroke of thispiston I01 forcing the fluid in the cylinder I06 past a discharge checkvalve 62" into the high pressure pipe line 63. Similarly, the suctionstroke of the piston I01 drawing water or other operating fluid pastsuction inlet check valve 60 into the pump chamber including the shortpipe" GI and the delivery stroke of thi piston I01 forc-' ing the fluidin the cylinder I06past a discharge 3 check valve 62 into the highpressure pipe line 63.

The action of the high pressure end of the differential piston is, ofcourse, dependent directly on the movement of the low pressure end bythe low pressure hydraulic fluid whiohis effected in substantially thesame manner -as the first'de-' scribed construction through theoperation of a main reversing valve H0 and auxiliary'differential pistontype valves I22 and I22 workingin the bores I23, I24 andI23,-I24,'respectively. The main reversing valv 0 works in aported linerI I4 and acts to direct the flow of low pressure hydraulic fluid frompipe II I either topipe:

I I2 connected with the right hand'end of the cylinder I05 or to pipeII2 connected to the left hand end of said cylinder I05-and'at the sametime connect the other of these pipes ;-I I2,

2' with the exhaust passage I34 connected to the hydraulic fluid supplytank through any suitable piping not shown. The bore I23 has a lowpressure port. I28, a-transfer port I26, and an exhaust port I29communicating therewith. The valve I22 isadapted-to connectthe portI26with the exhaust port I29--in its leftward 'shifted'position or toconnect port I26 with the port I28 in its rightward shifted position.Similarly, the

bore I23 has a low pressure port I28, a transferport I 26, and anexhaust port I29 communicating therewith. The valve I22 is adapted toconnect the port I26 with the low pressure port I28 as shown in itsleftward shifted position or to connect said port I26" with exhaust portI29 in its rightward shifted position.

As in the first described construction, the reversing valve has a lostmotion connectionwith the rams II9and II9- working in bores I 20 and I20in the valve casing I50 engaging the ends of a rod H8 which runs looselythrough an axially extending bore in the valve I I0, said rams havingstem extension passing through stufling boxes IOI at the ends of saidcasing. The bore I20 connects by a pipe I2I with the port I26, and abranch pipe I3I leads from an intermediate point of this pipe to thefront end of the bore I24. The bore I20 connects by a pipe I2I with theport I26, and a branch pipe I3I leads from an intermediate point thereofto the front end of the bore I24.

The ports I23 and I28 lead into a common passage connected with a pipeIII of low pressure oil or other suitable hydraulic fluid.

With the above arrangement, the piston II on the last part of itsmovement toward the left engages the projecting end of the valve I22 andshifts it to the left into the position shown in Fig. 2, therebyconnecting ports I 28 and I26 together, so that the driving low pressurehydraulic fluid from pipe III will flow through pipes I 2| and I3I, thusbringing pressure fluid against the ram II9 to move the reversing valveI I0 from the position shown in Fig. 2 toward the left and bringingpressure fluid into the bore I24 to shift the valve I22 to the left tothe position shown in the drawing. When this valve I22 is so shifted,the port I26 is connected with the exhaust port I29, and hence the boresI24 and I20 are connected to the exhaust through pipes I3I' and I2I withthe result that there is nothing interfering with the shifting of thereversing valve IIO toward the left and the continued positioning of thevalves I22 and I22 in the positions shown in the drawing until thepiston I01 moves from the position there shown to the right until itstrikes the projecting end of the valve I22. The piston is so moved tothe right by the movement of the reversing valve IIO to the left so asto connect pipes I I2 and I I I together while pipe H2 is connected tothe exhaust passage I34 and the supply tank connected therewith. Duringthe movement of the piston I0'I toward the right, the hydraulic fluid incylinder I06 drawn in past check valve 60 during the preceding leftwardstroke is forced out of said cylinder past the check valve 62 to thepipe 63' at the desired high pressure which is determined by the ratioof the diameters of the small and large pistons of the differentialpiston I01. On this movement to the right the piston I09 draws in a newcharge of hydraulic operating fluid past check valve 60 into cylinderI06. At the end of the travel of the piston III! to the right thepositions of the control valves I22 and I22 are reversed from that shownin the drawing while the reversing valve H0 is shifted to the right tothe position shown in Fig. 2 since shifting of the valve I22 tothe-rightconnects-ports -I 26 and "I 28*togethe-r and to pipes I2I and I3I which then-connectthe bore I20- of the reversing-valve mechanism andthe bore I24 of the-pilot valve'I22' with the low pressure motive fluidfrompipel I I, thereby first causing a shift of the valve I22-toward theright to connect the port I26 to the exhaustport I29 and through pipeI2I and I3'I' connect the forward end of bore I20-* of thereversingvalve mechanismand the bore I24 for the-pilot valve I22 with exhaust, sothat there-is then nothing to stop the shifting of the reversingvalve-llfl from the left to the right to the position-shown, and at thesame time holding the valve I22-inits rightward position.Shiftingof-the-valve--I I0=- to the position shown connects the-pipe lI2'-with the pressure fluid supply pipe III'and the pipe II2 with theexhaust "passage, so'thatthepiston I0! is drivento the-left totheposition shown in Fig. 2 while the right high pressure-piston I09 ison its suction and the left high pressure-piston I09 is on its deliverystroke. Thereafter; the cycle of operation is-repeated.

In this form of theinvention it is to be again noted that the reversingvalve- IIO-cannotbe operated to cause a-reversal of thepiston' I01 untilsaid piston reaches the end of its movement and the control or auxiliaryvalves are operated and that neither pilot valve I22 or I22 can beshifted during the intermediate travel of the piston and that theshifting of one controls the shifting to what may be termed the cookedposition of the other.

It is also to be noted that the lost motion connections between thereversing valve and its small operating rams aid in the shifting of theneversing valve, as either one of them is in motion when it engages thisvalve and thus acts to overcome the inertia of the heavier reversingvalve and promptly shift it to its reversed position. The lost motionconnections also provide a certain time delay or lag in the operation ofthe reversing valve, so that the control valves will be in their desiredpositions when the movement of the reversing valve occurs.

The hydraulic pressure booster above described corresp0nds in itsoperation with that of the actuating pump for furnishing the lowpressure fluid, so the boosters operation may be of variable or constantvolume depending upon the actuating pump.

I desire it to be understood that this invention is not to be limited tothe details of construction hereinbefore described except only in so faras such limitations are included in the ap ended claims.

What I claim as my invention is:

1. In a hydraulic booster having a cylinder, a motor piston operating insaid cylinder and a reversing valve for alternately respectivelyconnecting opposite ends of said cylinder with a source of hydraulicpressure fluid and exhaust, the combination with said piston and saidvalve of a pair of control Valves for said reversing valve, means foroperating said control valves alternately by the piston as it reachesthe end of its stroke, hydraulically operated means for returning saidcontrol valves, and means for hydraulically interlocking said controlvalves to prevent their movement except at the end stroke positions ofthe movement of the piston, said valves in turn preventing movement ofthe reversing valve until one of said valves has been operated and theother has been moved to a position for acutation by the piston on itsreturn stroke.

2. In a hydraulic booster having a pressure cylinder, a, motor pistonoperating in said cylinder and. a reversing valve'for alternatelyconnecting the opposite ends of the cylinder with a source of hydraulicpressure fluid and an exhaust, the combination with said piston and saidvalve of a .pair of control valves for said reversing valve, saidcontrol valves being disposable at the ends of the cylinder-in positionto be alternately engaged and moved by the piston as it reaches the endof its stroke, hydraulically operated means for returning said controlvalves and means for hydraulically interlocking said control valves toprevent their movement except at the end stroke positions of movement ofthe piston, said valves in turn preventing movement of the reversingvalve until one of said valves has been operated and the other has beenmoved to a position for actuation by the piston on its return stroke.

3. In a hydraulic booster having a cylinder, a motor piston operating insaid cylinder, and a reversing valve for alternately respectivelyconnecting the opposite ends of the cylinder with a source of hydraulicfluid under pressure and an exhaust, the combination with said reversingvalve of actuating rams for shifting said valve havinga lost motionconnection therewith so as to control the inlet and exhaust of pressurefluid to opposite ends of the cylinder, and control means controlled bythe piston at the end of its stroke in both directions for controllingthe operation of said rams.

4. In a hydraulic booster having a cylinder, a motor piston operating insaid cylinder, and a hydraulically operated reversing piston type valvefor alternately respectively connecting the opposite ends of thecylinder with a source of hydraulic pressure fluid and an exhaust, thecombination with said piston and valve of a pair of oppositely disposeddifferential piston type control valves mounted to have a part of theirreduced inner end project-inwardly into the-cylinder in the path of thepiston for shifting movement thereby in one direction, said controlvalves provided with hydraulically operated rams for shifting'saidvalves in the opposite direction, differential diameter bores for saidvalves, passages interconnecting the larger diameter bore of one of thevalves with the smaller diameter bore of the other valve, and passagescontrolled by said control valves'under the action of the piston forcontrolling the supply of hydraulic pressure fluid to operate saidreversing valve.

JOHN H. MCCORMICK.

CERTIF ICATE OF G ORRECTI ON Patent No. 2,296,6h7. September 22, 19b2,

JOHN H. McCORMICK.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 16, for 'bore 25" read -bore 25v-; page 1;, firsteolumn, line 1, strike out "pressure"; and that the said Letters Patentshould be read with this correction therein that the same may conform tothe rec:- ord of the case in the Patent Office.

Signed and sealed this 27th day of October, A. D. 1311.2.

1 Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

